Problem: Simplify the following expression: $k = \dfrac{5}{3x} - \dfrac{1}{6x}$
In order to subtract expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $3x$ and $6x$ $\lcm(3x, 6x) = 6x$ $ k = \dfrac{2}{2} \cdot \dfrac{5}{3x} - \dfrac{1}{1} \cdot \dfrac{1}{6x} $ $k = \dfrac{10}{6x} - \dfrac{1}{6x}$ $k = \dfrac{10 -1}{6x}$ $k = \dfrac{9}{6x}$ Simplify the expression by dividing the numerator and denominator by 3: $k = \dfrac{3}{2x}$